An ocular ultrasound uses sound waves to image parts of the eye and orbit that cannot be observed during a routine ocular exam. It is most commonly used to determine the presence or absence of a retinal detachment when a cataract blocks direct visualization of the retina.
Ocular ultrasound is not painful, and most patients do not require a sedative. Topical anesthetic is applied to the surface of the eye, and ultrasound gel is applied to the surface of the probe. When the ultrasound probe is placed on the eye, the sound waves it generates bounce off of different ocular structures in different ways, and as these reflected sound waves return to the probe, they are reconstructed into an image on a screen.
In addition to retinal detachments, ocular ultrasonography can be used to detect ocular and orbital tumors, intraocular hemorrhage, lens luxations, ocular foreign bodies, and various congenital ocular anomalies. Unfortunately, it cannot detect microscopic lesions such as retinal holes, which can progress to retinal detachments, nor can it always distinguish between intraocular tumors and blood clots, so other diagnostics may be recommended.